1. Field of the Invention
The field of art to which this invention pertains includes power transmission mechanisms and more specifically such mechanisms as have multiple forward and reverse constant-mesh gearing.
2. Description of the Prior Art
In multiple speed constant-mesh-gear reversible powershift type transmissions, it is desirable to arrange the transmissions' major components, or basic structure, in such a way that a variety of additional components or modifications may easily be added to this basic mechanism or structure. Transmissions of this type are mainly utilized in off-highway heavy duty vehicles and construction equipment which often are manufactured for specific requirements in only limited numbers. Thus, having a basic transmission structure which can readily be adapted to meet unique criteria is of paramount importance. Not only is cost reduced, but dependability and availability are improved. Such a family of basic transmissions is disclosed in U.S. Pat. No. 3,893,345 (issued July 8, 1975) to Sisson et al, which patent is also assigned to the assignee of this invention.
The main purpose of this invention is to provide a further modification of the basic or generic transmission mechanism disclosed in the aforesaid patent so that this basic mechanism may be easily modified to fulfill yet a further set of common requirements. This family of transmissions has a common denominator in the fact that regardless of the number of shafts utilized, they always lie in a common plane, preferably vertical. This allows the production of a family of constant-width transmissions, which not only greatly facilitate installation procedures but also permits the use of large numbers of common parts. The particular transmission embodiment wherein the improvement is applicable is a transmission wherein the output shaft is axially aligned with the input shaft and thus may be designated an "inline" transmission.